This invention relates to an apparatus and method useful in foundry operations for positioning molds correctly with respect to a pouring vessel prior to filling the molds with molten metal from the pouring vessel. The invention also relates to an apparatus and method for controlling the pouring of the molten metal into the molds. Particularly, this invention relates to the use of a non-contact distance measuring device, located above the mold, in conjunction with a control system, to control the position of a pouring vessel over the mold for dispensing the molten metal, and also to control the pour rate from the vessel during the filling of the mold.
Typically in foundry operations, molds have been positioned and filled manually and with simple mechanical apparatus. For example, a series of sand molds formed by a mold making machine would be conveyed successively to a mold pouring station, where the operator would adjust the position of a filling vessel based upon a visual estimate as to when the vessel was positioned directly over the pour opening of the mold. Similarly, when pouring molten metal from the vessel, the operator would adjust the valve of the vessel and the flow rate of the molten metal according to what he believed from past knowledge and experience was the rate necessary to completely fill the mold cavity and produce an acceptable end product. As is readily apparent, this approach is largely dependent upon the skill of the operator.
The present invention eliminates much of this inaccuracy and human error by utilizing a non-contact distance measuring device and control system to automatically control the positioning of the dispensing vessel and the pouring of molten metal therefrom.
Non-contact distance measuring devices, such as devices utilizing lasers, have been employed in a variety of manufacturing and industrial applications. Laser measuring devices, for example, have been used for such diverse applications as measuring fluid levels in bottles, performing quality control of machine parts, measuring the thickness of steel slabs, and numerous other areas wherein the flucuation of the distance to the surface of an object as it passes beneath a laser beam can be measured and correlated to a desired property or dimension of that article.
Exemplary systems utilizing non-contact distance measuring devices in manufacturing applications are disclosed in U.S. Pat. No. 3,565,531 to Kane et al, U.S. Pat. No. 3,633,010 to Svetlichy, U.S. Pat. No. 4,375,921 to Morander and U.S. Pat. No. 4,453,083 to Bohlander et al. Examples of systems in the specific area of filling molds with molten metal include U.S. Pat. No. 4,276,921 to Lemmens et al, U.S. Pat. No. 4,508,970 to Ackerman and a Modern Casting article, "Central Foundry Adapts Lasers to Foundry Operations" (March 1984).
However, these systems have not utilized the distance measuring device acting cooperatively with a dispensing vessel to control the positioning of the dispensing vessel over the pour cup opening of the mold cavity nor do these systems control the rate of pouring from the dispensing vessel in response to variations in the molten metal level in the mold pour cup.